3 ms·

The devices used to fabricate the floppy disks were not the same as the devices used by consumers. They had many more capabilities, infamously including the ab

The devices used to fabricate the floppy disks were not the same as the devices used by consumers. They had many more capabilities, infamously including the ability to adjust the write head to follow a spiral pattern (instead of concentric circular tracks).

joezydeco 8y ago
Spiral writing didn't mean a thing unless the consumer's drive could read it back. The more important part about spiral writing was that it defeated the track-by-track copy of most Apple ][ copy programs, since there was no disk position synchronization available on the consumer drives. Note that the Applesauce device modifies the drive to allow for this.
- bithead65 8y ago
  The only modification of the drive is the installation of a sync sensor that Woz removed (among all the other smarts in the drive to begin with).
- StillBored 8y ago
  IIRC, they were all defeated, except for the burn a hole in the disk and try to write to it copy protection mechanism. It was more a matter of which bit copy software had the right profile to be able to copy the tracks. Back when I was doing a lot of copying disks, I remember it was really important to get the drive speeds right for a given profile. That way the you could dead reconing style copy for a partial track once the drive sync'ed to some known pattern that was fully on the starting track. These copies obviously didn't work 100% of the time, but generally a few tries would yield a working copy. I personally used Copy][ Plus as my primary utility and vaguely remember writing little "scripts" (more a few bytes of hex codes IIRC that described which tracks to read, and how to do quarter stepping/etc) to describe how to copy spiral track disks. Although frequently, I remember it being easier to try one of a number of other bit copy utilities first.
  - colanderman 8y ago
    > the burn a hole in the disk and try to write to it copy protection mechanism Uhh, mind elaborating on this?
    - _russross 8y ago
      I remember this was a protection scheme, but I don't remember who used it. They would use a laser to burn a small hole in the disk. At load time, the program would attempt to write to the sector with the hole and then read it back. If it succeeded, they knew it was a copy. Basically, they created a disk that could accept writes everywhere except a certain sector, something you could not replicate with even a perfect copy.
      - buserror 8y ago
        Yes and that was VERY easily defeated too -- you just had to take the floppy, very carefully align the synchronization hole with your copy, and take a pinhead and make your own little scratch in the same place. It was a bit silly to be honest -- this was the easiest copy protection to bypass!
        hota_mazi 8y ago
        That won't work, because the actual disk inside the sleeve will never be aligned the same way your copy is. The protection is not the hole in the sleeve, it's the hole in the disk. For example, the garbage reads would happen on track 12, $230 bytes after the $D5 $AA $96 marker. Good luck physically reproducing this. These protections are trivial to remove in code, though.
        buserror 8y ago
        You clearly have never looked at a floppy before making "that won't work" comments, but floppies have a sync hole that is aligned. And having made multiple copies like that, I know very well it worked pretty well as a method -- it's very likely why that method never became the 'uncopiable' it was claimed to be when it came out.
kazinator 8y ago
The Apple II drives have this capability, which is why they can follow the data. The track-to-track motion is carried out by a stepper motor which is controlled with some memory mapped registers. To move from one track to another, the motor is stepped through four phases corresponding to "quarter track" increments. Some copy-protected software was written on using partial tracks, with quarter track increments. The software's loading routines knew how to follow that.
- StillBored 8y ago
  Hence the spiral tracks which were basically, a partial track written and then the head was stepped a quarter track and another partial track written, repeat. The copy protection was easy broken once you knew how much data needed to be read/written before stepping to the next track. Of course the sync sequence, or timing requirements to find the track once you stepped was helpful too.
  - function_seven 8y ago
    Let me see if I understand this. The disk authoring machine would lay down a true spiral, right? And the software controlling the read head would know this, and follow/emulate that spiral by stepping the head in a 1/4 track every 90°? So while the continuous spiral moved underneath the read head, the read head would mostly follow it but with some "quantization" error? (Not large enough to cause issue with reading, but impossible for an OS-level utility to replicate when copying the disk)
    - kazinator 8y ago
      The thing is, if the OS-level utility replicated that with quarter-track increments so that the same data is read back, it would be fooled. The consumer Apple II Drive (Disk II) has only quarter track increments; it cannot follow a smooth spiral. If a copy protection is based on a smooth spiral, it has to somehow depend on detecting the quantization errors due to the track skew, the absence of which reveals that there is a quantized, piece-wise spiral. If the skew didn't cause any issues with reading, then the software couldn't tell the difference between the smooth spiral and the fake staircased one.
hota_mazi 8y ago
The most popular and most devious ways to protect floppies on the Apple ][ were more or less all based on timing bits (including the most famous protection of all, the E7 slipstream). These timing bits were necessary on the disks for the reading head to be able to tell 1's from 0's, but copiers did not have the ability to maintain them, so copies were often desynchronized. AppleSauce is the only device that can successfully preserve timing bits, hence allowing protected disks to be copied. Source: I crack Apple ][ programs for fun.
deleted 8y ago
[deleted]
sp332 8y ago
Here's one where Track 6 is a bit-for-bit copy of Track 5 - including the header that says "This is Track 5"! https://archive.org/download/PinballConstructionSet4amCrack/Pinball%20Construction%20Set%20%284am%20and%20san%20inc%20crack%29.txt https://archive.org/download/PinballConstructionSet4amCrack/...
- diskblitz 8y ago
  That is a pretty standard EA protection. Pretty amazing stuff. 2 normal tracks typically have a crosstalk area between them (typically on the half track). But the EA tracks are perfect from 4.75-6.50. And the protection scheme actually sweeps the head back and forth across the range WHILE reading the data.
diskblitz 8y ago
They are actually just writing data to the concentric tracks, but just timing the steps between the tracks very carefully. When making a copy, you couldn't get the steps to sync up and so the timing for the steps would all be broken. High end commercial copiers really didn't come into play until 1984-5.

joezydeco 8y ago

Spiral writing didn't mean a thing unless the consumer's drive could read it back. The more important part about spiral writing was that it defeated the track-by-track copy of most Apple ][ copy programs, since there was no disk position synchronization available on the consumer drives. Note that the Applesauce device modifies the drive to allow for this.

bithead65 8y ago
The only modification of the drive is the installation of a sync sensor that Woz removed (among all the other smarts in the drive to begin with).
StillBored 8y ago
IIRC, they were all defeated, except for the burn a hole in the disk and try to write to it copy protection mechanism. It was more a matter of which bit copy software had the right profile to be able to copy the tracks. Back when I was doing a lot of copying disks, I remember it was really important to get the drive speeds right for a given profile. That way the you could dead reconing style copy for a partial track once the drive sync'ed to some known pattern that was fully on the starting track. These copies obviously didn't work 100% of the time, but generally a few tries would yield a working copy. I personally used Copy][ Plus as my primary utility and vaguely remember writing little "scripts" (more a few bytes of hex codes IIRC that described which tracks to read, and how to do quarter stepping/etc) to describe how to copy spiral track disks. Although frequently, I remember it being easier to try one of a number of other bit copy utilities first.
- colanderman 8y ago
  > the burn a hole in the disk and try to write to it copy protection mechanism Uhh, mind elaborating on this?
  - _russross 8y ago
    I remember this was a protection scheme, but I don't remember who used it. They would use a laser to burn a small hole in the disk. At load time, the program would attempt to write to the sector with the hole and then read it back. If it succeeded, they knew it was a copy. Basically, they created a disk that could accept writes everywhere except a certain sector, something you could not replicate with even a perfect copy.
    - buserror 8y ago
      Yes and that was VERY easily defeated too -- you just had to take the floppy, very carefully align the synchronization hole with your copy, and take a pinhead and make your own little scratch in the same place. It was a bit silly to be honest -- this was the easiest copy protection to bypass!
      - hota_mazi 8y ago
        That won't work, because the actual disk inside the sleeve will never be aligned the same way your copy is. The protection is not the hole in the sleeve, it's the hole in the disk. For example, the garbage reads would happen on track 12, $230 bytes after the $D5 $AA $96 marker. Good luck physically reproducing this. These protections are trivial to remove in code, though.
        buserror 8y ago
        You clearly have never looked at a floppy before making "that won't work" comments, but floppies have a sync hole that is aligned. And having made multiple copies like that, I know very well it worked pretty well as a method -- it's very likely why that method never became the 'uncopiable' it was claimed to be when it came out.

kazinator 8y ago

The Apple II drives have this capability, which is why they can follow the data. The track-to-track motion is carried out by a stepper motor which is controlled with some memory mapped registers. To move from one track to another, the motor is stepped through four phases corresponding to "quarter track" increments. Some copy-protected software was written on using partial tracks, with quarter track increments. The software's loading routines knew how to follow that.

StillBored 8y ago
Hence the spiral tracks which were basically, a partial track written and then the head was stepped a quarter track and another partial track written, repeat. The copy protection was easy broken once you knew how much data needed to be read/written before stepping to the next track. Of course the sync sequence, or timing requirements to find the track once you stepped was helpful too.
- function_seven 8y ago
  Let me see if I understand this. The disk authoring machine would lay down a true spiral, right? And the software controlling the read head would know this, and follow/emulate that spiral by stepping the head in a 1/4 track every 90°? So while the continuous spiral moved underneath the read head, the read head would mostly follow it but with some "quantization" error? (Not large enough to cause issue with reading, but impossible for an OS-level utility to replicate when copying the disk)
  - kazinator 8y ago
    The thing is, if the OS-level utility replicated that with quarter-track increments so that the same data is read back, it would be fooled. The consumer Apple II Drive (Disk II) has only quarter track increments; it cannot follow a smooth spiral. If a copy protection is based on a smooth spiral, it has to somehow depend on detecting the quantization errors due to the track skew, the absence of which reveals that there is a quantized, piece-wise spiral. If the skew didn't cause any issues with reading, then the software couldn't tell the difference between the smooth spiral and the fake staircased one.

hota_mazi 8y ago

The most popular and most devious ways to protect floppies on the Apple ][ were more or less all based on timing bits (including the most famous protection of all, the E7 slipstream). These timing bits were necessary on the disks for the reading head to be able to tell 1's from 0's, but copiers did not have the ability to maintain them, so copies were often desynchronized. AppleSauce is the only device that can successfully preserve timing bits, hence allowing protected disks to be copied. Source: I crack Apple ][ programs for fun.

deleted 8y ago

[deleted]

sp332 8y ago

Here's one where Track 6 is a bit-for-bit copy of Track 5 - including the header that says "This is Track 5"! https://archive.org/download/PinballConstructionSet4amCrack/Pinball%20Construction%20Set%20%284am%20and%20san%20inc%20crack%29.txt https://archive.org/download/PinballConstructionSet4amCrack/...

diskblitz 8y ago
That is a pretty standard EA protection. Pretty amazing stuff. 2 normal tracks typically have a crosstalk area between them (typically on the half track). But the EA tracks are perfect from 4.75-6.50. And the protection scheme actually sweeps the head back and forth across the range WHILE reading the data.

diskblitz 8y ago

They are actually just writing data to the concentric tracks, but just timing the steps between the tracks very carefully. When making a copy, you couldn't get the steps to sync up and so the timing for the steps would all be broken. High end commercial copiers really didn't come into play until 1984-5.